الفهرس 
Review of LiteratureOnly 14 pages are availabe for public view
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Abstract
It was to study the influence of fluoride releasing adhesive system on the quality of bond at resincomposite/dentin interface in terms of μTBS of resin-composite restorations to dentin, morphological changes and chemical analysis ofthe interface.The occlusal enamel of 80 human sound molar teeth was removed perpendicular to the long axis of teeth to expose flat dentin surface at a standardized depth. A specially constructed flat splitted Teflon mold(7x7mm and 4mm in thickness) was used for the fabrication of resincomposite specimens. Each tooth was then sectioned vertically in order to obtain four central sticks (beams).For μTBS testing, 72 molar teeth were selected. They were divided into two main groups of 36 molars each; according to the adhesive system used (A), namely, fluoride free adhesive system (A1) and fluoride releasing one (A2). Then each group was further subdivided into two subgroups of 18 molars each according to the type of resin-composite used (C). They were micro-hybrid resin-composite (C1), and nano-filled resin-composite (C2). Then, each subgroup was subdivided into two classes of nine teeth each, according to dentin treatment (D), namely;(D1) represents restored teeth kept in physiological saline (served ascontrol) and (D2) in which restored teeth were kept in a buffered demineralizing solution. Finally, each class was subdivided into three divisions of three teeth each, according to the storage period (T), in (T1)specimens were stored for one day (24 hours), and in (T2) specimenswere stored for three months while in (T3) specimens were stored for six months. from all sticks obtained from each class, 10 sticks were selectedresulting in a total of 240 specimens evaluated.Summary & Conclusion 97 Assessment of the μTBS was done using a Universal Testing Machine. Each beam was attached to the specially designed attachment jig and has its ends glued with dental adhesive. Data were recorded using computer software. A tensile load with compression mode of force was applied via materials testing machine at a crosshead speed of 0.5 mm/min. The applied tensile force resulted in debonding along the substrate-adhesive interface.For assessment of fluoride uptake by human dentin(ultramorphological and chemical analysis), eight molar teeth were selected in the present study. Prior to adhesive system application, each tooth was assessed for fluoride content (baseline) and assigned for (T0).Teeth were divided into two main groups of four molars each; according to the adhesive system used (A), namely a fluoride free (A1) and a fluoride releasing (A2). Then, they were restored with nanofilled resincomposite restorative material. Each group was subdivided into two subgroups of two molar teeth each according to dentin treatment (D);where (D1) specimens kept in physiological saline (served as control) and (D2) where specimens were kept in a buffered demineralizing solution.Each specimen was assessed for fluoride content after one month (T1)and three months (T2).To observe the morphology of hybrid layer, photographs were taken on the borderline surface between the adhesive and the dental structures. Specimens were analyzed, both qualitatively andquantitatively using ESEM and EDAX respectively. The ESEM is operating at 25.00 kV with secondary electron mode at 2000 X magnification. The device has the ability to capture an image for the sample with magnification up to 1000000 X.Summary & Conclusion 98 Within the limitations of this in vitro study, the following conclusions could be derived:1- Fluoride releasing adhesive system has an influential positive role in bonding quality of resin composites to demineralized dentin.2- Fluoride uptake capacity of dentin from adhesives varies according to the degree of mineralization.3- The μTBS of resin composite to dentin is affected by the filler loading, distribution, and particle size.4- Durability of bond effectiveness is adversely affected by time.5- Effectiveness of hybridization is not the issue of hybrid layer thickness.Recommendations:1- Further clinical studies are required to confirm data obtained from the present study.2- Fluoride releasing adhesives are recommended in cases when doubt about degree of mineralization of dentin exists.